New research released at the Royal College of Obstetricians and Gynaecologists (RCOG) 7th International Scientific Meeting in Montreal, has found that obesity significantly increases the risk of a subsequent pregnancy loss in women with recurrent miscarriages.

The study, from St Mary's hospital in London, aimed to investigate the effect of body mass index (BMI) on unexplained recurrent (three or more) miscarriage and included 696 women who attended a specialist clinic between 1996 and 2007.

All couples attending the clinic underwent comprehensive investigations and those with no identifiable cause established were referred to as "unexplained" recurrent miscarriage.

Each woman had her BMI measured at first consultation and was placed into one of four categories: underweight; normal; overweight; and obese.

In total, 1% (10/696) of the women were underweight, 54% (372/696) were of normal weight, 30% (211/696) were overweight and 15% (103/696) were obese.

In those who had a livebirth in their next pregnancy 11% were obese compared to 19% who had a future poor pregnancy outcome.

Advanced maternal age (≥35) and increased number of previous miscarriages were associated with poor pregnancy outcome.

When maternal age and number of previous miscarriages were adjusted, obese women were shown to have a significantly increased risk of a further miscarriage compared to those with normal weight (OR 1.73, CI 1.06 -2.83). There was no difference between those who were overweight (OR 1.27, CI 0.89 - 1.83) or underweight (OR 0.12, CI 0.15 - 1.00).

Ms Winnie Lo, Clinical Nurse Specialist at St Mary's Hospital, said "Ours is the first study to look directly at the link between BMI and recurrent miscarriage. It shows that obese women who experience recurrent miscarriage are at greater risk of subsequent pregnancy loss.

"All women with recurrent miscarriage should be weighed at their first consultation. Those who are found to be obese should be counselled regarding the benefits of weight loss in increasing their chances of a successful pregnancy and programmes should be in place to help with the weight loss process."

The Royal College of Obstetricians and Gynaecologists 7th International Scientific Meeting is taking place in Montreal from Wednesday 17th until Saturday 20th of September. The meeting is being held in conjunction with the Society of Obstetricians and Gynaecologists of Canada and the American College of Obstetricians and Gynecologists.

For further information and to see the scientific programme please visit: rcog2008/index.cfm.

Royal College of Obstetricians and Gynaecologists